Transition-metal dichalcogenides (TMDs) have been extensively researched due to their outstanding mechanical and electrical properties and show great potential in transistor engineering. However, studies have found that real device behaviors are far inferior to the theoretical expectation. One major limiting aspect of device performance occurs at the contact between metal and TMD layers in a transistor, and the smaller the size of the device, the more significant role the contact plays. Problems such as high contact resistance and inability to establish p-type contact between the metal and TMD layer hinder successful device implementation.